During insertion of the double lumen tube in patients with ankylosing spondylitis, cervical neutral position should be maintained to avoid vertebral and spinal injuries. Although flexible fiberoptic bronchoscopic intubation is the gold standard, available FOB size is not compatible with that of the endobronchial lumen of the double lumen tube. This problem should be solved according to institut...

BACKGROUND AND PURPOSE CT is a frequent examination that is performed using ionizing radiation. We sought to assess image-quality changes on CT scans of the head when the radiation dose is reduced by changing tube current and kilovoltage. METHODS A formalin-fixed cadaver was examined in conventional and helical mode by use of two CT-scanners. Surface dose was measured with standard scanning p...

A boundary element model for the computation of sequence-dependent hydrodynamic properties of short DNA molecules is introduced. The hydrated surface is modeled as a curved tube of uniform radius with ends capped by hemispheres, and the axis of the tube is a general space curve whose length and curvature are determined locally by the sequence using a rigid basepair model of double-helical DNA w...

The macrocyclic nonaaza 3 + 3 amine based on diaminocyclopentane forms enantiopure helical complexes with lanthanide(III) ions. In contrast to analogous complexes based on 1,2-trans-diaminocyclohexane, no clear helicity process is observed. Crystal structures of these compounds show tight helical wrapping of the macrocycle around the lanthanide(III) ion leading to the formation of a double heli...

The reaction of AgNO3 with 1-(4-pyridylmethyl)-1H-benzotriazole (4-pbt) afforded a photoluminescent onedimensional (1D) double-helical coordination polymer {[Ag(4-pbt)](NO3)} (1) formed by interchain C-H supramolecular interactions of the single-helical chains. Adjacent 1D double-helical motifs aforementioned were assembled into different two-dimensional (2D) sheets from the different crystallo...

Yeast phenylalanyl transfer RNA crystallizes in a simple orthorhombic unit cell (a = 33.2, b = 56.1, c = 161 A), and the crystal yields an x-ray diffraction pattern with a resolution of 2.3 A. From an analysis of the packing in the unit cell it is concluded that the molecular dimensions are approximately 80 by 33 by 28 A. The diffraction pattern viewed along the a-axis has a distribution charac...

We report six phases of high-density nano-ice predicted to form within carbon nanotubes (CNTs) at high pressure. High-density nano-ice self-assembled within smaller-diameter CNT (17,0) exhibits a double-walled helical structure where the outer wall consists of four double-stranded helixes, which resemble a DNA double helix, and the inner wall is a quadruple-stranded helix. Four other double-wal...

The linear pentadecapeptide antibiotic, gramicidin D, is a naturally occurring product of Bacillus brevis known to form ion channels in synthetic and natural membranes. The x-ray crystal structures of the right-handed double-stranded double-helical dimers (DSDH) reported here agree with 15N-NMR and CD data on the functional gramicidin D channel in lipid bilayers. These structures demonstrate si...

Base sequence information can be stored in the local structure of right-handed double-helical DNA (B-DNA). The question arises as to whether a set of rules for the three-dimensional readout of the B-DNA helix can be developed. This would allow the design of synthetic molecules that bind DNA of any specific sequence and site size. There are four stages of development for each new synthetic seque...